1. Field of the Invention
The present invention relates to a presence information providing system which can provide presence information in a form that is easily used by each application among a plurality of applications which are provided with presence information different in structure, and a method and a server thereof.
2. Description of Related Art
The configuration of a conventional presence service will be described with reference to FIG. 1. This follows a presence service model defined in RFC 2778: “A Model for Presence and Instant Messaging” published by IETF (Internet Engineering Task Force). In the description below, “presence information” of the presence service refers to information representing a state of a device or a state of a user of a device, e.g. information of “online” and “offline” indicating whether the device is connected to a network or not, information of “response possible” and “response impossible” indicating whether a user of a communication device can immediately respond or not, and so on. If some question arises as to the meaning of a term, a meaning defined in RFC 2778: “A Model for Presence and Instant Messaging” is followed in principle, but the meaning of the term is not limited thereto.
In FIG. 1, a presence service 100 is a service that provides presence information of a presentity P requested from a watcher W. The watcher is an entity requesting presence information of a desired presentity from the presence service and acquiring presence information from the presence service, and the presentity is an entity providing its own presence information to the presence service. If some question arises as to the meaning of a term, a meaning defined in RFC 2778: “A Model for Presence and Instant Messaging” is followed in principle, but the meaning of the term is not limited thereto.
As shown in FIG. 1, there is a presence server 10 as one example of an implemented form of the presence service 100. There is a presence service client PC having functions of both the presentity P3 and the watcher W3. The presence service client is an entity which provides a state of a client itself to the presence server using the function possessed by the presentity, and acquires presence information of a desired presentity from the presence server using the function possessed by the watcher.
As shown in FIG. 1, there may be a plurality of presentities P providing presence information to the presence service 100, and there may be a plurality of watchers W receiving presence information. Further, the presentity and the watcher of the presence service client PC or the like may be connected to the presence service as one service client.
As for the usage form of the presence service, it is necessary that one user should first check the state of another user being a communication partner when the user speaks to the communication partner in, for example, the instant message (IM) service, the push-to-talk (hereinafter referred to as “PTT”) service and the like, and the presence service is used for checking the state of the user being the communication partner.
For more detailed description of the usage form of the presence service as an example of the PTT service, the presence service client is a PTT client on a PTT-dedicated terminal or the like. The presence server is a presence server managing the state of the PTT client disposed on the network.
The PTT client uses its own presentity function to notify the presence server of information about the current state of the PTT client, i.e. calling, not-calling (response possible), being out of the radius of communication, or the like. The PTT client uses its own watcher to request the state of the PTT client of the communication partner from the presence server and receive the provision of presence information of the PTT client. The presence service is used such that the state of the PTT client of the communication partner is checked with display on a screen or the like of the PTT-dedicated terminal, and if the PTT client is in a response possible state, a new PTT session is established to communicate with the communication partner.
For the presence service described above, a plurality of presence services may be combined to provide presence information instead of using just one presence service. For example, in presence services in communication services for cellular phones and the like, presence services of a plurality of applications including communication services provided through cellular phones and the like, e.g. applications of call, PTT, electronic-mails, Web access, games and the like are combined.
There are cases where structures of presence information about presence services in the combination of a plurality of presence services do not coincide. In this case, if presence information provided by the presentity is provided directly to the watcher, the presence information is not appropriate information from a viewpoint of the watcher, and therefore it is necessary to absorb the inconsistency by some method to enable presence information to be exchanged.
As one method for absorbing the inconsistency of structures of the presence information described above, a technique has been proposed in which for interconnecting presence services of presence information structured in different ways, a presence information converting apparatus converting contents of presence information is provided in the presence service, whereby contents of presence information are mutually exchanged in accordance with a conversion rule managed by conversion rule managing means (see, for example, Japanese Patent Laid-Open No. 2003-186775).
However, if presence information is structured in different ways, the conventional method in which contents of presence information are converted by the presence information converting apparatus and presence services are interconnected has a problem such that a special apparatus or mechanism which would not be required for a single presence service should be provided on the existing presence service side, and thus labor, time and costs are required for work procedures for incorporation of the apparatus or mechanism in a system.